It’s officially Foo Fighters Week on Late Show with David Letterman and what better way to launch the perfect-idea-themed week with Foo Fighters doing a cover of Black Sabbath’s “War Pigs” sung by Zac Brown. Monday night on the late show did just that. Now, Brown doesn’t sound like Ozzy Osbourne, but he for sure made the song his own. It was a revved up four-guitar filled performance. And it rocked SO hard! The Foo Fighters are taking...